6 Colo. Code Regs. § 1007-2-B
Appendix B uses 40 CFR Part 258 (Solid Waste Disposal Facility Criteria, October 9, 1991) as a reference document. Part 258 reference numbers, contained herein, are intentionally used for cross reference to the federal document.
B1 Applicability [40 CFR 258.50]
Ground water monitoring requirements in the Appendix B may be waived by the Department after consultation with the local governing body having jurisdiction if the owner or operator demonstrates that there is no migration potential for hazardous substances, pollutants and contaminants from that solid waste disposal site and facility to ground water during the life of the facility and the post-closure care period. If ground water monitoring requirements are waived, the operator must continue to demonstrate that no potential exists for migration of hazardous substances, pollutants and contaminants from the facility. Such demonstration shall be evaluated by the operator and submitted to the Department and the local governing body having jurisdiction every five years. This demonstration must be certified by a qualified ground water scientist and approved by the Department, and be based upon:
(1) Site-specific field collected measurements, sampling, and analysis of physical, chemical, and biological processes affecting contaminant fate and transport, and
(2) Contaminant fate and transport predictions that maximize contaminant migration and consider impacts on human health and environment, and
(3) Distance to drinking water intakes.
B2 Ground water monitoring systems [40 CFR 258.51]
(A) A ground water monitoring system must consist of a sufficient number of monitoring wells installed at appropriate locations and depths which will yield ground water samples that:
(1) Represent the quality of background ground water that has not been affected by leakage from a unit. A determination of background quality may include sampling of wells that are not hydraulically upgradient of the waste management unit where:
(a) Hydrogeologic conditions do not allow the owner or operator to determine what wells are hydraulically upgradient; or
(b) Sampling at other wells will provide an indication of background ground water quality that is as representative or more representative than that provided by the hydraulically upgradient wells; and
(2) Represent the quality of ground-water at the relevant point of compliance specified in Section 2.1.15. The downgradient monitoring system must be installed at the relevant point of compliance specified by the Department under 40 CFR 258.40(D) that is capable of detecting ground water contamination. When physical obstacles preclude installation of ground water monitoring wells at the relevant point of compliance at existing units, the down-gradient monitoring system may be installed at the closest practicable distance hydraulically down-gradient from the relevant point of compliance specified by the Department under 40 CFR 258.40(D) that is capable of detecting ground water contamination.
(B) Monitoring wells must be cased in a manner that maintains the integrity of the monitoring well bore hole. This casing must be screened or perforated and packed with gravel or sand, where necessary, to enable collection of ground water samples. The annular space (i.e., the space between the bore hole and well casing) above the sampling depth must be sealed to prevent contamination of samples and the ground water. Ground water monitoring wells and points are designed and installed in accordance with applicable rules and regulations pursuant to the "Water Well and Pump Installation Contractor's Act", Title 37, Article 91, Part 1, CRS, as amended
(1) The owner or operator must document the design, installation, development, and decommission of any monitoring wells, piezometers and other measurements, sampling, and analytical devices. Documentation shall be placed in the operating record and shall be submitted to the Department and the local governing body having jurisdiction.
(2) The monitoring wells, piezometers, and other measurement, sampling, and analytical devices must be operated and maintained so that they perform to design specifications throughout the life of the monitoring program.
(C) The number, spacing, and depths of monitoring systems shall be:
(1) Determined based upon site-specific technical information that must include thorough characterization of the:
(a) Saturated thickness, ground water flow rate, ground water flow direction including seasonal and temporal fluctuations in ground-water flow; and
(b) Saturated and unsaturated geologic units and fill materials overlying the uppermost aquifer, materials comprising the uppermost aquifer, and materials comprising the confining unit defining the lower boundary of the uppermost aquifer; including, but not limited to: thicknesses, stratigraphy, lithology, hydraulic conductivities, porosities and effective porosities.
(2) Certified by a qualified ground water scientist and approved by the Department and the local governing body having jurisdiction. Wthin 14 days, the owner or operator must place documentation in the operating record and be submitted to the Department and the local governing body having jurisdiction.
(D) Alternative monitoring systems
Alternative monitoring systems may be approved by the Department based on site specific technical information. Alternative monitoring includes the following: vadose zone monitoring, wet/dry monitoring or other alternative monitoring systems that are sufficient to detect changes in the subsurface condition and/or contaminants from the facility at the relevant point of compliance.
B3 Ground water sampling and analysis requirements [40 CFR 258.53]
(A) The ground water monitoring program must include consistent sampling and analysis procedures that are designed to ensure monitoring results that provide an accurate representation of ground water quality at the background and downgradient wells installed in compliance with 40 CFR 258.51(A). The owner or operator must notify the Department and the local governing body having jurisdiction that the sampling and analysis program documentation has been placed in the operating record and the program must include procedures and techniques for:
(1) Sample collection;
(2) Sample preservation and shipment;
(3) Analytical procedures;
(4) Chain of custody control; and
(5) Quality assurance and quality control.
(B) The ground water monitoring program must include sampling and analytical methods that are appropriate for ground water sampling and that, accurately measure hazardous constituents and other monitoring parameters in ground water samples. Analytical methods shall be according to Colorado Department of Health guidelines, or an EPA approved method, for constituents listed in Appendix I and Appendix II.
(C) The sampling procedures and frequency must be protective of human health and the environment.
(D) Ground water elevations must be measured in each well immediately prior to purging, each time ground water is sampled. Changes in the rate and directions of ground water flow should be evaluated at a frequency appropriate to site-specific hydrogeologic conditions. Ground water elevations in wells which monitor the same waste management area must be measured within a period of time short enough to avoid temporal variations in ground water flow which could preclude accurate determination of ground water flow rate and direction.
(E) The owner or operator must establish background ground water quality in a hydraulically upgradient or background well(s) for each of the monitoring parameters or constituents required in the particular ground water monitoring program that applies to the solid waste disposal site and facility, as determined under 40 CFR 258.54(A) or 40 CFR 258.55(A). Background ground water quality may be established at wells that are not located hydraulically upgradient from the solid waste disposal site and facility if it meets the requirements of 40 CFR 258.51(A)(1).
(F) The number of samples collected to establish ground water quality data must be consistent with the appropriate statistical procedures determined pursuant to paragraph (G) of this section. The sampling procedures shall be those specified under 40 CFR 258.54(B) for detection monitoring, 40 CFR 258.55 (B) and (D) for assessment monitoring, and 40 CFR 258.56(B) for corrective action.
(G) Following collection of background constituent concentration data, the owner or operator must specify in the operating record one or more of the following statistical methods to be used in evaluating ground water monitoring data for each hazardous constituent. The statistical test chosen shall be conducted separately for each hazardous constituent in each well. Any changes in statistical methodology from the specified method(s) shall be reviewed and approved by the Department within two weeks of the request and entered into the operating record. After background data has been collected, a statistical analysis will be specified.
(1) A parametric analysis of variance (ANOVA) followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's mean and the background mean levels for each constituent.
(2) An analysis of variance (ANOVA) based on ranks followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent.
(3) A tolerance or prediction interval procedure in which an interval for each constituent is established from the distribution of the background data, and the level of each constituent in each compliance well is compared to the upper tolerance or prediction limit.
(4) A control chart approach that gives control limits for each constituent.
(5) A trend analysis approach to evaluate the significance of an apparent change in water quality overtime at a given well.
(6) Another statistical test method that meets the performance standards of 40 CFR 258.53(H). The owner or operator must place a justification for this alternative in the operating record and notify the Department of the use of this alternative test. The justification must demonstrate that the alternative method meets the performance standards of 40 CFR 258.53(H).
(H) Any statistical method chosen under 40 CFR 258.53(G) shall comply with the following performance standards, as appropriate:
(1) The statistical method used to evaluate ground water monitoring data shall be appropriate for the distribution of chemical parameters or hazardous constituents. If the distribution of the chemical parameters or hazardous constituents is shown by the owner or operator to be inappropriate for a normal theory test, then the data should be transformed, or a distribution-free theory test should be used. If the distributions for the constituents differ, more than one statistical method may be needed.
(2) If an individual well comparison procedure is used to compare an individual compliance well constituent concentration with background constituent concentrations or a groundwater protection standard, the test shall be done at a Type I error level no less than 0.01 For each testing period. If a multiple comparisons procedure is used, the type I experiment wise error rate for each testing period shall be no less than 0.05; However, the type I error of no less than 0.01 for individual well comparisons must be maintained. This performance standard does not apply to tolerance intervals, prediction intervals, or control charts.
(3) If a control chart approach is used to evaluate ground water monitoring data, the specific type of control chart and its associated parameter values shall be protective of human health and the environment. The parameters shall be determined after considering the number of samples in the background data base, the data distribution, and the range of the concentration values for each constituent of concern.
(4) If a tolerance interval or a prediction interval is used to evaluate ground water monitoring data, the levels of confidence and, for tolerance intervals, the percentage of the population that the interval must contain, shall be protective of human health and the environment. These parameters shall be determined after considering the number of samples in the background data base, the data distribution, and the range of the concentration values for each constituent of concern.
(5) The statistical method shall account for data below the limit of detection with one or more statistical procedures that are protective of human health and the environment. Any practical quantitation limit (PQL) that is used in the statistical method shall be the lowest concentration level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions that are available to the facility.
(6) If necessary, the statistical method shall include procedures to control or correct for seasonal and spatial variability as well as temporal correlation in the data.
(I) The owner or operator must determine whether or not there is a statistically significant increase over background values for each parameter or constituent required in the particular ground water monitoring program that applies to the solid waste disposal site and facility, as determined under 40 CFR 258.54(A) or 40 CFR 258.55(A).
(1) In determining whether a statistically significant increase has occurred, the owner or operator must compare the ground-water quality of each parameter or constituent at each monitoring well designated pursuant to 40 CFR 258.51 (A)(2) to the background value of that constituent, according to the statistical procedures and performance standards specified under paragraphs (G) and (H) of this section.
(2) Within 30 days after completing sampling and analysis, the owner or operator must determine whether there has been a statistically significant increase over background at each monitoring well and notify the Department.
B4 Detection monitoring program [40 CFR 258.54]
(A) Detection monitoring is required at solid waste disposal sites and facilities at all ground water monitoring wells defined under 40 CFR 258.51 (A)(1) and (A)(2) of this part. At a minimum, a detection monitoring program must include the monitoring for the constituents listed in Appendix IA of this part. A detection monitoring program for solid waste disposal site and facility must also include the monitoring for constituents listed in Appendix IB.
(1) The Department after consultation with the local governing body having jurisdiction may delete any of the Appendix I monitoring parameters for a solid waste disposal site and facility on a site specific basis, if it can be shown that the removed constituents are not reasonably expected to be in or derived from the waste contained in the facility.
(2) The Department after consultation with the local governing body having jurisdiction may add to the Appendix IA or IB monitoring parameters for a solid waste disposal site and facility on a site specific basis. The additional analytes will be selected using the following minimum criteria:
(a) An "acceptable" analytical method exists. An acceptable method should be validated to demonstrate it is capable of generating reliable data on a routine basis. Additionally, it should be standardized and thus readily available from commercial laboratories.
(b) A calibration standard is commercially available and readily obtainable.
(c) The analyte is chemically stable in the sample matrix with appropriate but not unreasonable collection and preservation techniques.
(d) If there exists a reasonable expectation that the additional analyte will be present due to site specific conditions, or the additional analyte will be a reliable indictor of ground water chemistry and possible precursor to other more hazardous constituents that may be released later from the solid waste disposal site and facility.
(3) In determining the addition or deletion of Appendix IA or IB constituents, the Department shall consider the following factors:
(a) The types, quantities, And concentrations of constituents in wastes managed at the solid waste disposal sites and facilities, and
(b) The mobility, stability, and persistence of waste constituents or their reaction products in the unsaturated zone beneath the mswlf unit.
(B) To establish background concentrations, a minimum of eight quarterly samples from each well must be collected and analyzed for the Appendix IA & IB constituents, or the list approved in accordance with paragraph (A) of this section. The Department may specify an appropriate monitoring frequency for repeated sampling and analysis for Appendix IA & IB constituents, or the list approved in accordance with paragraph (a) of this section, during the active life and the post-closure care period. The monitoring frequency during the active life (including closure) shall be no less than semi-annual, unless approved by the Department. The alternative frequency shall be based on consideration of the following factors:
(1) Lithology of the saturated and unsaturated zone;
(2) Hydraulic conductivity of the ground water and unsaturated zone;
(3) Ground water flow rates;
(4) Minimum distance between upgradient edge of the solid waste disposal site and facility unit and downgradient monitoring well screen (minimum distance of travel); and
(5) Resource value of the ground water.
(6) For landfills this schedule shall be no less stringent than 40 CFR 258.54(B).
(C) If the owner or operator determines, pursuant to 40 CFR 258.53(G) of this part, that there is a statistically significant increase over background for one or more of the constituents listed in Appendix I a or IB or the list approved in accordance with paragraph (A) of this section, at any monitoring well at the boundary specified under 40 CFR 258.51 (A)(2), the owner or operator:
(1) Must place documentation in the facility operating record indicating which constituents have shown statistically significant changes from background levels and forward the documentation to the Department and the local governing body having jurisdiction within 14 days; and
(2) Must establish an assessment monitoring program meeting the requirements of 40 CFR 258.55 of this part within 90 days except as provided for in paragraph (3) below.
(3) May demonstrate that a source other than a SWDSF caused the contamination or that the statistically significant increase resulted from error in sampling, analysis, statistical evaluation, or natural variation in ground water quality. A report documenting this demonstration must be certified by a qualified ground water scientist and approved by the Department and the local governing body having jurisdiction and be placed in the operating record. If a successful demonstration is made and documented, the owner or operator may continue detection monitoring as specified in this section. If, after 90 days, a successful demonstration is not made, the owner or operator must initiate an assessment monitoring program as required in 40 CFR 258.55.
B5 Assessment monitoring program [40 CFR 258.55]
(A) Assessment monitoring is required whenever a statistically significant increase over background has been detected for one or more of the constituents listed in the Appendix IA or IB or in the list approved in accordance with 40 CFR 258.54(A)(1) & (a)(2).
(B) Within 90 days of triggering an assessment monitoring program, and annually thereafter, the owner or operator of a sanitary landfill must sample and analyze the ground water for all constituents identified in Appendix II of this part. A minimum of one sample from each potentially affected well must be collected and analyzed during each sampling event. For any constituent detected in the these wells as a result of the complete Appendix II analysis, a minimum of four independent samples, or an alternate sampling schedule approved by the Department, from each well (background and downgradient) must be collected and analyzed to establish background for the constituents. The Department may specify an appropriate subset of wells to be sampled and analyzed for Appendix II constituents during assessment monitoring. The Department may delete any of the Appendix II monitoring parameters for a MSWLF unit if it can be shown that the removed constituents are not reasonably expected to be in or derived from the waste contained in the unit.
(C) Solid waste disposal sites and facilities, other than sanitary landfill, must also conduct an assessment monitoring program. The parameters of the assessment monitoring program shall be determined by the owner or operator and the Department based on consideration of:
(1) The types, quantities and concentrations of constituents in wastes managed at the solid waste disposal site and facility, and
(2) The mobility, stability, and persistence of waste constituents or their reaction products in the unsaturated zone beneath the solid waste disposal site and facility.
(D) The Department may specify an appropriate alternate frequency for repeated sampling and analysis for the full set of Appendix II constituents or the list approved in accordance with 40 CFR 258.55(C), during the active life (including closure) and post-closure care of the unit considering the following factors:
(1) Lithology of the aquifer, monitored and unsaturated zone;
(2) Hydraulic conductivity of the aquifer, monitored and unsaturated zone;
(3) Ground water flow rates;
(4) Minimum distance between upgradient edge of the MSWLF unit and downgradient monitoring well screen (minimum distance of travel);
(5) Resource value of the aquifer and monitored unit; and
(6) Nature (fate and transport) of any constituents detected in response to this section.
(E) After obtaining the results from the initial or subsequent sampling events required in 40 CFR 258.55(B), (C) and (D), the owner or operator must:
(1) Wthin 14 days, place documentation in the operating record identifying the detected Appendix II constituents or the list approved in accordance with 40 CFR 258.55(C), and submit the documentation to the Department and the local governing body having jurisdiction;
(2) Wthin 90 days, and on a semiannual basis thereafter:
(a) Resample all wells specified by 40 CFR 258.51(A);
(b) Conduct analyses for all constituents in Appendix IA & IB or in the alternative list approved in accordance with 40 CFR 258.54(A)(2), and for those constituents in Appendix II or the list approved in accordance with 40 CFR 258.55(C) that are detected in response to 40 CFR 258.55(B), (c) and (d); and
(c) Record their concentrations in the facility operating record and submit them to the Department and the local governing body having jurisdiction.
(3) At least one sample from each well must be collected and analyzed during these sampling events. The Department may specify an alternative monitoring frequency during the active life (including closure) and the post-closure period for the constituents referred above to in this paragraph. The alternative frequency for Appendix IA & IB constituents, or the list approved in accordance with 40 CFR 258.54(A)(2), during the active life (including closure) shall be no less than annual. The alternative frequency shall be based on consideration of the factors specified in 40 CFR 258.55(D);
(F) If the concentrations of all Appendix II constituents are shown to be at or below background values, using the statistical procedures in 40 CFR 258.53(G), for two consecutive sampling events, the owner or operator must document and submit this finding to the Department and the local governing body having jurisdiction, and may, upon approval from the Department and the local governing body having jurisdiction discontinue assessment monitoring.
(G) If one or more Appendix II constituents or the list approved in accordance with 40 CFR 258.55(C) are detected at statistically significant levels above the background concentrations, the owner or operator shall, within 14 days of this finding, place a document in the operating record identifying the Appendix II constituents or the list approved in accordance with 40 CFR 258.55(C) that have exceeded the background concentrations and submit the documentation to the Department and all appropriate local government officials. The owner or operator shall also:
(1) (a) Characterize the nature and extent of the release by installing additional monitoring wells as necessary;
(b) Install at least one additional monitoring well at the facility boundary in the direction of contaminant migration and sample this well in accordance with 40 CFR 258.55(D)(2);
(c) Notify all persons who own the land or reside on the land that directly overlies any part of the plume of contamination if contaminants have migrated off-site if indicated by sampling of wells in accordance with 40 CFR 258.55(G)(1); and
(d) Initiate an assessment of corrective measures as required by 40 CFR 255.56 Of this part within 90 days; or
(2) Demonstrate that a source other than a mswlf unit caused the contamination, or that the statically significant increase resulted from error in sampling, analysis, statistical evaluation, or natural variation in ground water quality. A report documenting this demonstration must be certified by a qualified ground water scientist or approved by the Department and placed in the operating record. If a successful demonstration is made the owner or operator must continue monitoring in accordance with the assessment monitoring program pursuant to 40 CFR 258.55, and may return to detection monitoring if the Appendix II constituents or the list approved in accordance with 40 CFR 258.55(C) are at or below background as specified in 40 CFR 258.55(E). Until a successful demonstration is made, the owner or operator must comply with 40 CFR 258.55(G) including initiating an assessment of corrective measures in accordance with 40 CFR 258.56.
B6 Assessment of corrective measures [40 CFR 258.56]
(A) Within 90 days of finding that any of the constituents referenced in 40 CFR 258.55 have been detected at a statistically significant level exceeding the background concentrations, the owner or operator must initiate an assessment of corrective measures. Such an assessment must be completed within a reasonable period of time as determined by the Department and governing body having jurisdiction.
(B) The owner or operator must continue to monitor in accordance with the assessment monitoring program as specified in 40 CFR 258.55.
(C) The assessment shall include an analysis of the effectiveness of potential corrective measures in meeting all of the requirements and objectives of the remedy as described under 40 CFR 258.57, addressing at least the following:
(1) The performance, reliability, ease of implementation, and potential impacts of appropriate potential remedies, including safety impacts, cross-media impacts, and control of exposure to any residual contamination;
(2) The time required to begin and complete the remedy;
(3) The costs of remedy implementation; and
(4) The institutional requirements such as state or local permit requirements or other environmental or public health requirements that may substantially affect implementation of the remedy(s).
(D) The owner or operator shall provide to the Department the results of the corrective measures assessment, prior to the remedy selection. The Department and the local governing body having jurisdiction shall provide a 30 day public notification and public comment period to interested and affected parties prior to the remedy selection.
(E) In the interest of minimizing environmental contamination and promoting effective remediation, owners or operators shall evaluate pursuant to Appendix B, Section B6, Subsection (F) the need for undertaking interim measures prior to the selection of the final remedy.
(1) The owner or operator shall evaluate the need for interim measures within 30 days of the date of determining that there has been a statistically significant increase over background and shall submit the evaluation to the department and the local governing body having jurisdiction.
(2) Within 30 days after the determination is made that interim measures are needed, the owner or operator shall submit documentation to the department and the local governing body having jurisdiction of their intention to implement the interim measure and an implementation schedule.
(3) Wthin 14 days of receipt of documentation, the department shall notify the owner or operator of any conditions to be imposed and any recommended modifications to be employed during the implementation of the interim measure.
(5) The interim measures, as approved by the department, shall be initiated as soon as possible but no later than 30 days after the receipt of the department's approval.
(6) The owner or operator shall provide periodic progress reports on the implementation of interim measures to the department and the local governing body having jurisdiction and incorporate the interim measures in the results of the corrective measures assessment as required in 40 CFR 258.56(d).
(F) Interim measures should, to the greatest extent practicable, be consistent with the objectives of and contribute to the performance of any remedy that may be required pursuant to 40 CFR 258.57. The following factors must be considered by an owner or operator in determining whether interim measures are necessary:
(1) Time required to develop and implement a final remedy;
(2) Actual or potential exposure of nearby populations or environmental receptors to hazardous constituents;
(3) Actual or potential contamination of drinking water supplies or sensitive ecosystems;
(4) Further degradation of the ground water that may occur if remedial action is not initiated expeditiously;
(5) Weather conditions that may cause hazardous constituents to migrate or be released;
(6) Risks of fire or explosion, or potential for exposure to hazardous constituents as a result of an accident or failure of a container or handling system; and
(7) Other situations that may pose threats to human health and the environment.
B7 Selection of remedy [40 CFR 258.57]
(A) Based on the results of the corrective measures assessment conducted under 40 CFR 258.56, remedies must:
(1) Be protective of human health and the environment;
(2) Attain the ground water protection standard as specified pursuant to 40 CFR 258.55 (G) and (H);
(3) Control the source(s) of releases so as to reduce or eliminate, to the maximum extent practicable, further releases of constituents referenced in 40 CFR 258.55 into the environment that may pose a threat to human health or the environment; and
(4) Comply with standards for management of wastes as specified in 40 CFR 258.58(D).
(B) In selecting a remedy that meets the requirements of 40 CFR 258.57(A), the owner or operator shall consider the following evaluation factors:
(1) Extent and nature of contamination;
(2) Resource value of the ground water including:
(a) Current and potential uses;
(b) Proximity and withdrawal rate of users;
(c) Ground water quantity and quality;
(d) The hydrogeologic characteristic(s) of the saturated zones beneath the facility and surrounding land; and
(e) The cost and availability of alternative water supplies.
(3) The long-term and short-term effectiveness and protectiveness of the potential remedy(s) based on consideration of the following:
(a) The type and degree of long-term management required, including monitoring, operation, and maintenance;
(b) Short-term risks that might be posed to the human health and the environment during implementation of such a remedy, including potential threats associated with excavation, transportation, and redisposal or containment;
(c) Time until the remedy becomes effective;
(d) Potential for exposure of humans and environmental receptors to remaining wastes;
(e) Long-term reliability of the engineering and institutional controls; and
(f) Potential need for refinement of the remedy.
(4) The effectiveness of the remedy in controlling the source to reduce further releases based on consideration of the following factors:
(I) The extent to which containment practices will reduce further releases;
(II) The extent to which treatment technologies may be used; and
(III) The practical capabilities of remedial technologies in achieving compliance with ground water protection standards established under 40 CFR 258.57(G) and (H), and other objectives of the remedy.
(5) The ease or difficulty of implementing a potential remedy(s) based on consideration of the following types of factors:
(I) Degree of difficulty associated with constructing the technology;
(II) Expected operational reliability of the technologies;
(III) Need to coordinate with and obtain necessary approvals and permits from other agencies;
(IV) Availability of necessary equipment and specialists;
(V) Available capacity and location of needed treatment, storage, and disposal services;
(VI) Desirability of utilizing technologies that are not currently available, but which may offer significant advantages over already available technologies in terms of effectiveness, reliability, safety, or ability to achieve remedial objectives; and
(VII) Ground water removal and treatment costs.
(6) Practicable capability of the owner or operator, including a consideration of the technical and economic capability.
(7) The degree to which community concerns are addressed by a potential remedy(s).
(8) Other relevant factors.
(C) If the owner or operator is unable to meet the requirements of 40 CFR 258.57(A) the Department after consultation with the local governing body having jurisdiction may determine that remediation of a release of constituents referenced in 40 CFR 258.55 is not necessary if the owner or operator demonstrates to the satisfaction of the Department that:
(1) The ground water is additionally contaminated by substances that have originated from a source other than the solid waste disposal site and facility and those substances are present in concentrations such that cleanup of the release from the SWDSF would provide no significant reduction in risk to the human health and the environment; or
(2) The constituent(s) is present in ground water that is not hydraulically connected to the uppermost aquifer or surface water.
(3) Remediation results in unacceptable cross-media impacts.
(4) Obtain certification of a qualified ground water scientist or approval by the Department that compliance with requirements under 40 CFR 258.57(A) cannot be practically achieved with any currently available methods.
(5) A cost-benefit analysis indicates that remediation of the release is unacceptable.
(D) A determination by the Department pursuant to 40 CFR 258.57(C) shall not affect the authority of the Department to require the owner or operator to undertake source control measures or other measures that may be necessary to eliminate or minimize further releases to the ground water; to prevent exposure to the ground water; or control exposure of human health and environment to residual contamination.
(E) The owner or operator shall specify as part of the selected remedy, a schedule(s) for initiating and completing remedial activities or source control. Such a schedule must require the initiation of remedial activities or source control within a reasonable period of time taking into consideration the factors set forth in paragraphs 40 CFR 258.57(B) or 40 CFR 258.57(D).
(F) The owner or operator must submit a report to the Department and the local governing body having jurisdiction and place it in the operating record, within 14 days of selecting a remedy(s) or source control measure(s). The report shall describe the selected remedy(s) or source control measure(s) and how it meets the requirements of section 40 CFR 258.57. Within 60 days of the reports receipt, the Department after consultation with the local governing, body having jurisdiction shall provide a determination, in conformance with Section 40 CFR 258.57 of the adequacy of the remedy(s) or source control measure(s).
(G) The owner or operator shall develop ground water protection standards which are required to implement a corrective measure pursuant to 40 CFR 258.57. The ground water protection standards shall not be implemented without approval by the Department. The ground water protection standard for each constituent, referenced in 40 CFR 258.55, that has been detected at a statistically significant level exceeding background shall be based on the following:
(1) Background concentration for the constituent in wells established in accordance with 40 CFR 258.51 (A);
(2) Maximum contaminant level (MCL) promulgated under Section 1412 of the safe drinking water act (codified) under 40 CFR Part 141;
(3) Health based levels that satisfy the following criteria:
(a) The level is derived in a manner consistent with guidelines for assessing the health risks of environmental pollutants (51 FR 33992, 34006, 34014, 34028);
(b) The level is based on scientifically valid studies conducted in accordance with the toxic substances control act good laboratory practice standards ( 40 CFR Part 792) or equivalent;
(c) For carcinogens, the level represents a concentration associated with an excess lifetime cancer risk level (due to continuous lifetime exposure) with the 1 x 10.4 To 1 x 106 range; and
(d) For systemic toxicants, the level represents a concentration to which the human population (including sensitive subgroups) could be exposed on a daily basis that is likely to be without appreciable risk of deleterious effects during a lifetime. For purposes of this subpart, systemic toxicants include toxic chemicals that cause effects other than cancer or mutation.
(H) The owner or operator, and the Department in consultation with the local governing body having jurisdiction may consider establishing alternate ground water protection standards to 40 CFR 258.57(G), based on consideration of the following:
(1) Multiple contaminants in the ground water;
(2) Exposure threats to sensitive environmental receptors;
(3) Other site-specific exposure or potential exposure to ground water; and
(4) Best demonstrated available technology.
B8 Implementation of corrective measures [40 CFR 258.58]
(A) Based on the schedule established under 40 CFR 258.57(D) for initiation and completion of remedial activities the owner or operator must:
(1) Establish and implement a corrective action ground water monitoring program that, at a minimum:
(a) Meets the requirements of an assessment monitoring program under 258.55;
(b) Indicates the effectiveness of the corrective action remedy; and
(c) Demonstrates compliance with ground water protection standard pursuant to 40 CFR 258.58(E).
(2) Implement the corrective action remedy selected under 40 CFR 258.57;
(B) An owner or operator or the Department in consultation with the local governing body having jurisdiction may determine, based on information developed after implementation of the remedy, source control or other information, that compliance with requirements of 40 CFR 258.57 are not being achieved. In such cases, the owner or operator must implement other methods or techniques in compliance with the requirements of section 40 CFR 258.58(C).
(C) All wastes that are generated during the implementation of the remedy(s) or source control measure(s) required under 40 CFR 258.57, or an interim measure required under 40 CFR 258.58(A)(3), shall be managed in a manner:
(1) That is protective of human health and the environment; and
(2) That complies with applicable Resource Conservation and Recovery Act requirements.
(D) Remedies selected pursuant to 40 CFR 258.57 shall be considered complete when:
(1) The owner or operator complies with the ground water protection standards established under 40 CFR 258.55 (G) and (H) at all points within the plume of contamination that lie beyond the ground water monitoring well system established under 40 CFR 258.51(A).
(2) Compliance with the ground water protection standards established under 40 CFR 258.55 (G) and (H) has been achieved by demonstrating that concentrations of constituents referenced in 40 CFR 258.55 have not exceeded the ground water protection standard(s) for a period of three consecutive years using the statistical procedures and performance standards in 40 CFR 258.53(G) and (H). The Department may specify an alternative length of time during which the owner or operator must demonstrate that concentrations of constituents referenced in 40 CFR 258.55 have not exceeded the ground water protection standard(s) based on the following factors:
(a) Extent and concentration of the constituents) released;
(b) Chemical and physical characteristics of the hazardous constituents in the ground water and geologic media;
(c) Accuracy of monitoring or modeling techniques, including any seasonal, meteorological, or other environmental variabilities that may affect the accuracy; and
(d) Chemical and physical characteristics of the ground water and geologic media.
(3) All actions required to complete the remedy have been satisfied.
(E) Upon completion of the remedy, the owner or operator and qualified ground water scientist must certify that completion of the remedy is in compliance with 40 CFR 258.58(D). A report shall be submitted to the Department and the local governing body having jurisdiction and placed in the operating record, within 14 days of certification. Within 60 days receipt of the report, the Department after consultation with the local governing body having jurisdiction shall provide a determination that the corrective action has met the requirements of 40 CFR 258.58(D).
(F) Upon completion of the certification process pursuant to 40 CFR 258.58(E), the owner or operator shall be released from the financial assurance requirement for corrective action under Section 1.6.
6 CCR 1007-2-B